Rotary fan



' April 7,1925.

- 1,532,827 G. c. LEWIS ROTARY FAN Filed Feb. 21. 1923 lNVENTOR:

/ ATTORIKES.

Patented Apr. 7, 1925,

1,532,827 OFFICE.

GEORGE C. LEWIS, OF PHILADELPHIA, PENNSYLVANIA.

ROTARY FAN.

Application filed February 21, 1923. Serial No. 620,342.

T all whomit may concern:

Be it known that I, GEORGE C. LEWIS, a citizen of the United States, residin in the city and county of Philadelphia, tate of Pennsylvania, have invented a new and use ful Rotary F an, of which the following is a specification.

My invention relates to the art of fan blade construction of the general type in which thin blades are mounted ,upon and rotatable with a blade hub, the assemblage of the blades being confined within a pcripheral rim which is a part of the fan as a whole and serves to confine in the desired circumferential disposition the outer ends of the blades.

My invention further relates to fans em ployed in cooling, heating and ventilating systemsfor public and industrial buildings,

theaters and so forth. y

In many particulars the blades which my invention comprehends possess some general similarity of construction and mode of operation to the blades of propellers for ships,

sometimes known as propeller fans,and its primary objectis a fan construction the blades of which considered as an assemblage, are as such reversible and equally efficient in either direction of rotation for exhausting or for blowing, a resultant'of the fact that both faces of the fan wheel are identical.

A further object is a blade construction of a simple and inexpensive character, which in efficiency of performance is better than that of the same general type now in use.

With the foregoing and other objects in View, my invention comprehends a fan. of 40 (he i'nultiple-blade disc type, the radially disposed blades of which embody certain old features of formation such as intake edges and leaving edges, but which also embody new formations which serve to expel the air in directions parallel with the axis of the hub and fan shaft, and which also embody twist formations, so to speak, of the body of the blades which are typically illustrated in the accompanying drawings and hereinafter described.

In a good embodiment of the foregoing blade construction the peripheral edge of each blade is turned at a less sharp angle to the axis of the fan shaft than is the hub or base edge, the result of which positioning is that the angle with respect to the axis of the shaft at the base of the blades compensates for the lesser speed at that point as compared with the speed at the periphery of the wheel, and tends also to equalize the effect of the blades on the air at the various points along their lengths.

In other words,,and by reason of the variable angles of the blades, practically the same velocity is given the air at or near the hub as is given to it at or near the periphery, with the result that an even flow of air is obtainedover the whole face ,of the Wheel and the back-flow common in the present types of disc fans prevented at or near the center of the fan, for the reason that the pressure there is suflicientto prevent the return and consequent short-circuiting of the air as delivered through the outer circumference of the wheel.

All of the foregoing advantages result from the novel and special formation of the blades which while the same as to each blade may be slightly varied as hereinafter described, the'angular relationship of the peripheral and basal edges being subject to variance t'o'meet different conditions.

Referring to the drawings, Figure 1 represents a front elevation of a typical embodiment of my fan.

Figure 2 represents a central, vertical, partly sectional and partly elevational side elevation of the fan of Figure 1. W

Figure 3 represents a diagrammatic plan illustrative of a preferred angular relationship of the peripheral and the basal edges of a blade.

Figure 5 represents a face elevation of a preferred form of, one 'of my fan. blades; and v [Figure 5 represents a skeleton diagram of a sectoral portion, so to speak, of my fan, flattened for easier understanding.

Similar. numerals of reference indicate corresponding parts.

Referring to Figures 1 and 2 of thedrawings, 1 designates a casing of any preferred form for supporting the fan shaft 2 and the preferably hollowed blade hub 3 of the fan as an entirety.

4: designates bearings in the casing for the fan shaft and'5 a driving pulley typical of any driving means.

The foregoing structure as a whole is sim-' ply one of convenience, as other well known constructions may be substituted for it.

l he blades being counterparts, a descrip- Ill) tion of one will be sufficient, and referring to Figures 3 and 4: the body portion-of the blade is, for purposes of explanation, embodied in three planes: a central plane 6, and two side planes 7 and S which along their respective outer edges are oppositely turned to form an intake edge 9 and a leaving edge 10.

The blade as an entirety may therefore be considered as comprising .the planes 6, 7 and 8, and the edges 9 and 10.

in the relative outlining, so to speak, of the planes, each blade has aconical outline, the continuous peripheral edge '11 :being wider than the COHUDUOUSbELSQl or hub edge- 12, as clearly illustrated in Figures 2, 3 and d. V

In the mounting of the parts, I 'find it convenient to attach the "basal edges :12 of the blades to the vhub 3 by blade plates 13 to which the blades are riveted or otherwise attached, and which themselves are attached to the rim 14 of the hollow hub by threaded stems 15 disposed at the desired inclination with reference to each other and secured by nuts 17.

The attachment of the peripheral edges of the blades to the inner circumference of the rim 18 of the wheel may be effected in many ways, as, for instance, by slotted grooves or channels in the riin, -it is essential, however, that the angle of attachment should not be parallel to that of the basal edges.

Upon Figure l, 1 have dotted imaginary divisional lines between the central plane and the side planes of a blade, and this 1 have done not for the purpose of having it understood that actual divisional lines er tist between the planar surfaces of which the body of the blade is composed, but simply to enable me to explain that the three planes are in asense separated so that they do not all lie ina =C0hlll1011 flat plane but, relatively to each other, lie in planes -dilier-. ing in angular -CllSPOSltiOD;-tllilll is to say that while the central plane 6 is flat, the side plane 7 is upwardly angular to it and the side-plane 8 downwardly angular to it.

The effect of this, so to speak, relatively angular disposition of these three planar surfaces, is to impart to the body of the blade as a 'Wl'lOle a shape or conformation new in the art and calculated to impart, and in fact imparting, whichever way the blades may be placed within their mounting, an even flow Ofltll O-bllillIlQClOVQZ the entire .surfaceof the wheel and also preventing the back-flow .hereinbefore explained winchever way the wheel may be rotated or what- ;ever way it may be set to face.

It is further to be explained that while 1 have illustrated the three planes of ablade each as a flat surface or plane proper, I do not confine myself to such flat surfaces but utilize curved or in a sense spoonlike surfaces bearing the same general relationship to each other as the flat planes 6, 7 and 8, but relatively, oppositely inclined, that is to say, the curvature of the plane 7 being the opposite of that of the plane 8.

The lines of merger of the .inneredges of these two planes 7 and 8 When of curved formation, with the edges of the central plane, are also curved, and not angu'lar, it a'being further understood that when 6, 7 and S are true planes, their line of merger on the dotted lines need not be vangular but may be curved.

Having thus described my invention what I claim as new and desire .to secure by Letters Patent, is

In a rotary fan of the multiple-blade type, the combination of casing to support a fan shaft, a. fan shaft adjustably' supported in said casing, a plurality of counterpart blades which each embody oppositely inclined intake edges and leaving edges, and

the body portion of each 0f which is composed of three radially extending surfaces the continuous peripheral edges of which are of greater breadth than the continuous basal edges,a hub fixed to said shaft and to which the basal edges of the blades are secured .at an angle :to its axis,means for securing said basal edges to the rotary hub at an angle to its -axis,acylindric rim -encoinpassin-g the peripheral edges of the blades and :to which said peripheral edges are secured at an angledift'erent from that of the connection of the basal edges with the 2hu:h,-and means for securing said peripheral ledges to said lim,-w hereby in the mounting a radial twist is imparted to each blade.

7 GEORGE LEYVIS.

Witnesses:

J. BONSALL Tarn-on, MCVAY. 

